Fujitsu Corporation

Nobuhiro Fujimoto

Hiroyuki Rokugawa

Satoshi Kuroyanagi

Kazuhiro Tanaka

Hiroyuki Nobuhara

Kiyohide Wakao

Jun Sato

Kazuyuki Mori

Tomohiro Ishihara

Atsuki Taniguchi

Shigefumi Masuda

Takaaki Wakisaka

Tadashi Ikeuchi

Mobile communication apparatus, of small size and low cost, may be installed in vehicles to afford enhanced mobile-to-mobile communications between preceding and succeeding vehicles, even over a great distance therebetween. In the preceding vehicle, a detector detects a carrier transmitted from the succeeding vehicle and a transmission controller uses the carrier, when detected, for transmitting data to the succeeding vehicle. Further, the detector in the preceding vehicle detects, from the carrier transmitted from the succeeding vehicle, whether the distance to the succeeding vehicle is in a range permitting two-way communications therebetween. The transmission controller in the preceding vehicle transmits first information to the succeeding vehicle when the detector does not detect the possibility of two-way communication, and transmits second information to the succeeding vehicle when the detector detects the possibility of two-way communications with the succeeding vehicle.

Mobile communication apparatus

An optical processing device for converting a wavelength of an optical signal comprises an optical processing unit supplied with an input optical beam carrying thereon one or more optical signals with respective wavelengths that are different from each other, the optical processing means being further supplied with a control optical beam having a stabilized reference wavelength and selecting the optical signal that has a first wavelength and outputting the same with a second wavelength that is specified by the reference wavelength; and a control unit for controlling the optical processing unit by specifying the first wavelength of the optical beam to be selected.

Optical processing device operating in a wavelength-synchronized mode

An optical processing device for converting a wavelength of an optical signal comprises an optical processing unit supplied with an input optical beam carrying thereon one or more optical signals with respective wavelengths that are different from each other, the optical processing means being further supplied with a control optical beam having a stabilized reference wavelength and selecting the optical signal that has a first wavelength and outputting the same with a second wavelength that is specified by the reference wavelength; and a control Unit for controlling the optical processing unit by specifying the first wavelength of the optical beam to be selected.

In one aspect of the present invention, a coding part of a transmitter side codes N series of input data into N+1 series of transmission data so that each of N+1 series of transmission data have frames and have the same transmission rates as those of the input data. For example, a bit transfer unit comprised in the coding part moves i-th bits of series i to the additional series N+1 where i=1 to N and a complement bit insertion unit inserts complements of an (N+1)-th bit of series 1 and (j-1)-th bits of series j into a first bit position of series 1 and j-th bit positions of series j, respectively, wherein J=2 to N. A frame signal insertion unit units alternate frame signal into the series N+1. BSI is secured by this simple construction.

Parallel transmission through plurality of optical fibers

A parallel transmission method includes a submethod of transmitting portion for transmitting parallel data of a plurality of channels as encoded data of a plurality of lines and a submethod of receiving portion for decoding parallel data of a plurality of lines from encoded data of the plurality of channels. The submethod of transmitting portion includes the steps of multiplying the frequency of a clock by a predetermined number to generate a multiplexing clock, separating input signals composed of parallel data of a plurality of channels and additional data for code transformation into a plurality of groups, transforming parallel data into serial data with the multiplexing clock, mutually substituting the resultant data of the plurality of channels from time to time, and generating encoded data containing the additional data of the plurality of lines. The submethod of receiving portion includes the steps of synchronizing encoded data of the plurality of lines with the additional data, substituting the resultant data of the plurality of lines in the inverse order of the transmitting portion, removing the additional data from the resultant data, successively arranging the resultant data of each group, dividing the frequency of a transmission clock by a predetermined number to generate an original clock, and transforming serial data of each group into parallel data.

Parallel code transmission method and apparatus of the same

The present invention relates to an optical receiving pre-amplifier and an optical receiver using the same. The object of the invention is to provide an optical receiving pre-amplifier having an enlarged dynamic range to a large output swing, and an optical receiver having a simplified circuit configuration and a sufficient eye aperture and suitable for a parallel transmission. The optical receiving pre-amplifier includes an input FET 10 with a gate terminal 10a to receive a current signal from a light receiving element and an output FET 12 with the gate terminal 12a connected to the signal terminal 10b of the input FET 10 to amplify and output the current signal to a predetermined voltage signal. A feedback resistor 14 is connected between the gate terminal 10a of the input FET 10 and the output terminal 19 of the output FET 12. A current source 15 can enlarge an output potential amplitude of the output FET 12 to a light signal change and is arranged between the gate terminal 10a of the input FET 10 and the power source 17.

Pre-amplifier for optical receiving and optical receiver using the same

An integrated semiconductor laser array apparatus which is simple in structure and yet capable of stabilizing the light output from each individual semiconductor laser element. The integrated semiconductor laser array apparatus includes a semiconductor laser array provided by integrating a plurality of semiconductor laser elements. The semiconductor laser array includes a master semiconductor laser element selected from the plurality of semiconductor laser elements and slave semiconductor laser elements constituted of the remaining semiconductor laser elements. A laser beam output from the master semiconductor laser element is sensed by a photodiode and thereby a photocurrent corresponding to the received light ,intensity is generated and the bias current for the master semiconductor laser element is controlled by a first bias current control circuit such that the generated photocurrent is kept constant. The bias current for each of the slave semiconductor laser elements is controlled by a second bias current control circuit depending on the output from the First bias current control circuit such that the ratio between the bias current for the master semiconductor laser element, and the bias current for each of the plurality of slave semiconductor laser elements is kept constant.

Integrated semiconductor laser array apparatus

A photonic switching system includes an optical link conversion board having a first end and a second end opposite to the first end, a plurality of wavelength converter elements arranged at a constant pitch along the first end of the optical link conversion board and converting input optical signals into optical signal components having different wavelengths, a combiner for combining the optical signal components received from the wavelength converter elements into an optical signal which includes optical signal components having a plurality of wavelengths, a plurality of light output parts arranged at a constant pitch along the second end of the optical link conversion board, and a deflector for sequentially deflecting the optical signal from the combiner to an arbitrary one of the light output parts in response to a control signal so that the optical signal at the arbitrary light output part includes a plurality of optical signal components having different wavelengths.

Photonic switching system

An optical drop-and-insert apparatus which can process an optical signal in the form of an optical signal without converting the optical signal into an electric signal. The optical drop-and-insert apparatus expands the pulse width of an optical data pulse in an optical data pulse train on an optical highway and drops the optical data pulse to form an empty bit at the bit of the optical data pulse or another bit so that a new optical data pulse may be inserted into the empty bit. Miniaturization of the apparatus and increase in processing speed can be attained by enabling processing of an optical signal while it remains in the form of an optical signal.

Optical drop-and-insert apparatus

A phase adjusting circuit for adjusting a phase of each bit of serial data by synchronizing with a system clock. The phase adjusting circuit includes a plurality of registers. Each bit of data is input into a corresponding one of the plurality of registers in a predetermined cyclic order, synchronized with a receiving clock which is extracted from the data, and outputting outputs of the registers in parallel. The outputs are each selected in a selector circuit under a control of the selector control signal in the same order as the above input to the registers. The selector control signal is generated by detecting a phase relationship between phases of the receiving clock and the system clock, and generating a selector control signal having a phase which is determined according to the phase relationship. Then, each bit of the above selected output is synchronized with the system clock.

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Kawasaki, Japan

Nobuhiro Fujimoto